The heart and circulatory system

Question 1

What is a singular circulatory system?

Answer 1

In singular circulatory systems, the blood is pumped from the heart to the gas exchange organ and then directly to the rest of the body

Question 2

What are double circulatory systems?

Answer 2

In double circulatory systems, the blood is pumped back from the heart to the gas exchange organ, back to the heart and then to the rest of the body

Question 3

Advantages of a double circulatory system?

Answer 3

Higher blood pressure and greater flow of blood to the tissues

Question 4

Blood flow through the heart (order)

Answer 4

Left atrium, left ventricle, aorta, vena cava, right atrium, right ventricle, pulmonary artery, lungs, pulmonary vein

Question 5

Cardiac cycle

Answer 5

Blood enters the atria, valves open, blood passes through ventricles, ventricles comtract, (because of increased pressure in ventricles valves close), semi-lunar valves open, blood rushed through pulmonary artery and cycke repeats

Question 6

Deoxygenated blood passes through these blood vessels, valves and parts of the heart:

Answer 6

Vena cava, right atrium, tricuspid valve, right ventricle, semilunar valve and pulmonary artery. It then moves onto the lungs

Question 7

How many times does the heart beat per minute?

Answer 7

About 70 times per minute but it can vary due to circumstances. The accelerator and decelerator nerve increases and decreases heart rate respectively (with the force of contractors?..)

Question 8

What effect does exercise have on heart rate?

Answer 8

Muscles need to release more energy and need more oxygen so the heart pumps more blood and more often to increase the amount of oxygen the muscles get

Question 9

What effect does stress have on heart rate?

Answer 9

When stressed, you are tense and being pumped with adrenaline and therefore need more blood (ie. Oxygen) in your muscles, due to flight or flight responses

Question 10

What effect does sleep have on heart rate?

Answer 10

Heart rate decreases as our organs are working slower. They then need to release less oxygen, because they need to release less energy

Question 11

What other things can effect heart rate?

Answer 11

Other things such as geographical position and age can also effect the heart rate

Question 12

Control of the heart rate

Answer 12

Osmoreceptors in aorta sense CO2 levels; Cardiac centre in medulla receives information via sensory nerve; cardiac centre sends nerve impulses via accelerator/decelerator nerves; pacemaker increases (/decreases) heart rate; blood pressure increases(/decreases)

Question 13

What are the effects of adrenalin on heart rate?

Answer 13

Adrenaline stimulates pacemaker to increase heartrate

Question 14

What is coronary heart disease?

Answer 14

It is the blockage of the coronary artery, which results in the blood supply to area of heart muscle cut off, less oxygen and glucose reaches heart muscle, the area of heart muscle cannot respire which results in a HEART ATTACK

Question 15

Risk factors for coronary heart disease?

Answer 15

No exercise, fatty foods, smoking, genetics, stress, age, being male

Question 16

Blood is pumped around a closed circuit made up of the heart and blood vessels. As it travels around it collects materials from some places and unloads them in others. In mammals, blood transports:

Answer 16

Oxygen from the lungs to all other parts of the body// carbon dioxide from all parts of the body to the lungs// nutrients from the gut to all parts of the body// urea from the liver to the kidneys

Question 17

Pulmonary circulation:

Answer 17

Transports blood to and from the lungs to exchange O2 and CO2 with air

Question 18

Systemic circulation:

Answer 18

Transports blood to and from the body to exchange O2 and CO2 with body cells

Question 19

What is the function of the placenta?

Answer 19

To supply the baby with nutrition and oxygen as well as to remove carbon dioxide and urea

Question 20

Arteries: (key info)

Answer 20

Arteries carry blood from the heart to organs in the body. Blood pressure high, blood oxygenated except in PULMONARY ARTERY, no valves except in AORTA and PULMONARY ARTERY

Question 21

Artery structure

Answer 21

Thick wall with muscle fibres and elastic tissue, small lumen, endothelium

Question 22

Vein : (key info)

Answer 22

The vein carries blood from organs back to heart, low blood pressure, deoxygenated (therefore dark red colour) except in PULMONARY VEIN, no valves

Question 23

Vein structure

Answer 23

Thin wall with little muscle and elastic tissue, large lumen, endothelium

Question 24

Capillary: (key info)

Answer 24

Capillaries carry blood through organs exchanging oxygen, glucose and carbon dioxide, low blood pressure, blood deoxygenated (starting oxygenated ending up deoxygenated after exchange), no valves

Question 25

Capillary structure

Answer 25

One cell thin endothelium

Question 26

Why do veins have valves?

Answer 26

To prevent the back-flow of blood

Question 27

Why are capillary walls only 1 cell layer thick?

Answer 27

To allow materials to pass through their walls easily

Question 28

High levels of blood cholesterol can lead to the narrowing of arteries. Suggest how this might affect the ability of the heart to function

Answer 28

When an artery is blocked, less blood and therefore glucose and oxygen reach heart cells. (This means that there is less aerobic respiration and more anaerobic respiration. Lactic acid builds up.) The heart has to contract harder to move blood past the blockage, which increases blood pressure in the coronary artery. If the plaque ruptures, a blood clot may form. This could lead to a heart attack if the coronary artery os blocked.

Question 29

Composition of blood

Answer 29

Cells, solute, liquid

Question 30

What is blood plasma?

Answer 30

Liquid part of the blood (mainly water) //carries the blood cells around the body, carries dissolved nutrients, nutrients, carbon dioxide and urea //distributes heat around the body

Question 31

Phagocytes

Answer 31

Much larger cells with a large spherical or lobed nucleus, phagocytes engulf bacteria and other microorganisms have infected our bodies

Question 32

Lymphocytes

Answer 32

Produce antibodies to destroy microorganisms, some lymphocytes persist in our blood after infection and give us immunity to specific diseases

Question 33

Platelets

Answer 33

The smallest cells (platelets are really fragments of other cells), platelets release chemicals to make a blood clot when we cut ourselves

Question 34

Explain how oxygen passes through from the mother to the baby

Answer 34

Oxygen diffuses out of maternal capillaries into intervillous space from high concentration to low and travels towards the foetus’ heart in the foetal veins

Question 35

What (other) functions does the placenta have?

Answer 35

Prevents/reduces the number of large molecules or microbes from passing from the mother to the foetus, so protects foetus from microbial infections, stops mothers immune system (antibodies)attacking the foetus, makes progesterone

Question 36

Why Is it important that the mother’s and foetus’ blood supply don’t mix?

Answer 36

So that harmful substances/microbes are prevented from reaching the foetal blood (they have to cross the wall of the villus to get to the foetal blood, few substances can do this)

Question 37

Why can it be harmful for the developing baby if the mother smokes?

Answer 37

If the mother smokes, there is less oxygen supplied to the baby, because pf carbon monoxide. This is harmful as it leads to babies habing a potentially low birth mads

Question 38

Why do we need a circulatory system, but amoeba don’t?

Answer 38

Amoeba are small enough to absorb nutrients and oxygen via diffusion, but we have a circulatory system to transport substances to and from their cells as diffusion is not possible (we are much larger than amoeba)